To link to the entire object, paste this link in email, IM or documentTo embed the entire object, paste this HTML in websiteTo link to this page, paste this link in email, IM or documentTo embed this page, paste this HTML in website

SUBCLINICAL ATHEROSCLEROSIS IN OVERWEIGHT LATINO YOUTH:
INFLUENCE OF CARDIOMETABOLIC RISK FACTORS
by
Claudia M. Toledo-Corral
______________________________________________________________________
A Dissertation Presented to the
FACULTY OF THE USC GRADUATE SCHOOL OF THE
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(PREVENTIVE MEDICINE)
December 2010
Copyright 2010 Claudia M. Toledo-Corral

Cardiovascular disease is the leading cause of death in the general population. Arterial inflammation and damage manifests as arterial thickening and is the pathological basis for atherosclerosis. The first signs of atherosclerosis are thought to begin in childhood and can be assessed using non-invasive ultrasound measures of the carotid intima media thicknees (CIMT). Children with any of the traditional cardiovascular risk factors, such as obesity or the metabolic syndrome may have early signs of undetectable, or subclinical, atherosclerosis. The purpose of this dissertation was to investigate subclinical atherosclerosis risk in overweight Latino youth with a family history of type 2 diabetes. The specific aims of this dissertation were: 1) to evaluate whether persistence of the metabolic syndrome, a clinically relevant tool, was associated with CIMT; 2) to examine if temporal changes in visceral adiposity and insulin resistance contributed to CIMT; and 3) to assess the progression of CIMT over a 2-year period. The over arching hypothesis was that in a cohort of high-risk children, the metabolic syndrome and related mechanisms such as abdominal adiposity and insulin resistance would be associated with increased CIMT. Participants were recruited from the on-going longitudinal Study of Latino Adolescents at Risk (SOLAR) Project, which examines type 2 diabetes risk in overweight Latino adolescents by use of total and regional body composition (via DEXA and MRI), as well as measures of insulin/glucose metabolism using OGTT and FSIVGTT with Bergman’s Minimal Modeling.; In paper 1, participants who had persistent metabolic syndrome over a 3-year period had significantly higher CIMT (0.647±0.018mm) compared to those who never had the metabolic syndrome, (0.600±0.007mm, p<0.01). In paper 2, participants in the highest CIMT tertile maintained levels of fasting glucose above 90mg/dL over a 3-year period prior to CIMT measurement, whereas the low and middle CIMT tertiles had a 3-4% decrease over time (p<0.05). All participants declined in insulin sensitivity over time (p<0.05). In paper 3, it was shown that a high variability in the magnitude of CIMT change exists in growing overweight Latino youth (mean progression: 0.017±0.003mm; +2.8% and mean regression: -0.019±0.002mm; -3.1%). Baseline LDL-cholesterol was the sole predictor of CIMT progression and the odds of CIMT progression increased by 3% for each 1 mg/dL higher baseline LDL-cholesterol [95% confidence interval (CI), 1.004-1.006, p=0.03]. In conclusion, measures of insulin action were not associated with CIMT or progression of CIMT. Elevated baseline CIMT was associated with a 3-year history of persistent metabolic syndrome, persistent high blood pressure, persistent high waist circumference and maintenance of fasting glucose levels above 90mg/dL. CIMT progression that was beyond the physiological norm over a 2-year period (CIMT >0.100mm) was solely predicted by baseline LDL-cholesterol.

SUBCLINICAL ATHEROSCLEROSIS IN OVERWEIGHT LATINO YOUTH:
INFLUENCE OF CARDIOMETABOLIC RISK FACTORS
by
Claudia M. Toledo-Corral
______________________________________________________________________
A Dissertation Presented to the
FACULTY OF THE USC GRADUATE SCHOOL OF THE
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(PREVENTIVE MEDICINE)
December 2010
Copyright 2010 Claudia M. Toledo-Corral